1. Field of Invention
The present invention relates to a stereo-image display technology. More particularly, the present invention relates to an autostereoscopic display apparatus, by which users can see the stereo-image just by naked eyes within a range of viewing angle.
2. Description of Related Art
Image is an effective method for transferring information. Along with the improvement of science and technology, besides the image printed on the paper, many images are displayed in digital on a display device. As the display screen of the display device is a plane structure formed by a pixel array, there is no stereoscopic display effect.
However, according to the visual characteristic of human eyes, a stereo-image may be produced when the left and the right eyes respectively see the two images with the same image but different parallax. The former stereoscopic display technology exports the two images utilizing the polarization effect, and users need to put on the polarized glasses to see the stereoscopic effect. The stereoscopic display mode is not convenient in use.
Next, the autostereoscopic display technology has been developed associating with digital display technology. However, the main bottleneck of the current autostereoscopic display technology is that it can not have both of high display resolution and wide view angle simultaneously. Most of the technologies divide the pixels on the display device into multiple groups and guide them into different directions so as to form multiple viewing zones, accordingly, users can see different images from different directions. Users can obtain stereoscopic display effect when viewing the images in different viewing zones through the two eyes. However, when users' two eyes are not in an appropriate specific location, users can not see the stereo-image. The number of the divided groups of the pixels must be increased in order to let users see the stereo-image in any viewing angle. Accordingly, in the condition that the total quantity of the physical pixels in the display device is a fixed number, the resolution of the image would be compromised. For example, when the pixels are divided into two groups, the resolution is substantially reduced into a half. In other words, the more the number of the divided groups of the pixels is, the lower the resolution would be.
Also, in order to maintain the image resolution and have more viewing zones, more hardware space and guiding structures must increase, resulting in the increase of the volume of the display device.
Therefore, how to simultaneously have both of high resolution and high freedom of viewing locations is the problem for the manufacturers or the designers.